The present invention relates to a heat-shrinkable sleeve intended to be applied on an object to be covered, defined by an inner surface and an outer surface and comprising means for controlling the uniform heating thereof.
One of the problems raised by the application of a heat-shrinkable sleeve onto an object is that of the feeding of heat to the sleeve. In particular, in the event that the sleeve is of substantial thickness, it is difficult to heat it uniformly throughout its entire thickness and over its entire length without the risk of locally burning the sleeve as a result of an excessive application of heat.
In order to guide the operator in effecting the heating of the sleeve it is known to provide marks in a colored material on the outer surface of the sleeve, the color of the marks changing when the sleeve has reached a predetermined temperature, thereby serving as a guide for the operator.
Such marks effectively facilitate the effecting of the heating of the sleeve, particularly when the sleeve is of slight thickness. However, when the sleeve is of substantial thickness, these marks are not fully satisfactory. In fact, as these marks are arranged on the outer surface of the sleeve they can give a precise indication of temperature only for a portion of the sleeve close to said outer surface, while the temperature of a portion furthest to the inside of the sleeve is not determined accurately.